House Targaryen, dragonriding and genetics

A popular belief amongst fans, perpetuated by commentary from characters in the books to show that it is widely believed in-universe, is that House Targaryen only ever practised incestuous marriage.

They certainly were fond of incest, and this was because of their Valyrian heritage. More particularly, their dragonriding heritage. This recently came up on /r/asoiaf where a new fan believed they had cracked a theory, but it’s actually just stated directly in the text: the dragonlords practised incest to maintain their ability to control their dragons.

What is not stated is why this was necessary, but from what we do know about taming dragons, there is more than a component of blood magic. But it’s not always necessary.

That’s the why. This blog is about the who.

Valyria and the Doom

The Valyrian Empire exploded in the Doom. Most of the Valyrian dragonlords died in the Doom, but some were away from Valyria when things went kabluey.

Aenar Targaryen and his children, and houses sworn to serve them such as the Celtigars and Velaryons, were the only real survivors of the Doom. There were other Valyrians who were away from Valyria by chance rather than by plan, but their time was rather limited:

Some accounts claim that a few others survived too, for a time. It is said that some Valyrian dragonlords in Tyrosh and Lys were spared, but that in the immediate political upheaval following the Doom, they and their dragons were killed by the citizens of those Free Cities.

Realistically, after the Doom, the Targaryens were the only remaining dragonlords on Planetos.

This is what Archmaester Gyldayn (who may or may not be GRRM in the context of the joint authoring of TWOIAF between GRRM, Elio and Linda?) has to say about the Targaryens. I’ve bolded the parts that make me go “hmmm.”

The Targaryens were of pure Valyrian blood, dragonlords of ancient lineage. Twelve years before the Doom of Valyria, Aenar Targaryen sold his holdings in the Freehold and the Lands of the Long Summer and moved with all his wives, kin and children to Dragonstone…

The Targaryens were far from the most powerful of the dragonslords, and their rivals saw their flight to Dragonstone as an act of surrender, as cowardice. But Lord Aenar’s maiden daughter Daenys, known forever afterwards as Daenys the Dreamer, had foreseen the destruction of Valyria by fire….

[description of Dragonstone’s location] … enabled both the Targaryens and their close allies, the Velaryons of Driftmark (a lesser house of Valyrian descent) to fill their coffers off the passing trade.

… for the best part of a hundred years after the Doom of Valyria (the rightly named Century of Blood) House Targaryen looked east, not west, and too little interest in the affairs of Westeros. Gaemon Targaryen, brother and husband to Daenys the Dreamer, followed Aenar the Exile as Lord of Dragonstone… Gaemon’s son Aegon and his daughter Elaena ruled together after his death. After them the lordship passed to their son Maegon, his brother Aerys, and Aerys’ sons Aelyx, Baelon and Daemion… whose son Aerion then succeeded to Dragonstone [and was the father of Visenya, Aegon and Rhaenys]

So from this we know a few things:

  • Aenar Targaryen was the first Targaryen to relocate from Valyria to Dragonstone
  • This is the family tree of the early Targaryens. There are 5 generations between the Targaryens who landed on Dragonstone (counting Aenar and his children Gaemon and Daenys as one ‘generation’)


  • We don’t have details of who everyone married, but we know that Gaemon married his sister Daenys, their son Aegon married their daughter Elaena, and of course Aegon married his sisters Visenya and Rhaenys. It seems that the early Targaryens only married outside of the family when they only had boys – thus necessitating a different Valyrian bride.
  • We also know that Aenar Targaryen had wives – plural. So from this we can deduce two things: the Valyrians had no issue with polygamy and incest.

Was this unique to House Targaryen, or generally all dragonriders? Did all Valyrians do this, or just the dragonlords?

Well, GRRM Archmaester Gyldayn answers this last question: (emphasis added)

The tradition amongst the Targaryens had always been to marry kin to kin. Wedding brother to sister was thought to be ideal. Failing that, a girl might we an uncle, a cousin, or a nephew; a boy, a cousin, aunt or niece. This practice went back to Old Valyria, where it was common amongst many of the ancient families, particularly those who bred and rode dragons. “The blood of the dragon must remain pure,” the wisdom went. Some of the sorcerer princes also too more than one wife when it pleased them, though this was less common than incestuous marriage. In Valyria before the Doom, wise men wrote, a thousand gods were honoured, but none were feared, so few dared to speak against these customs.

So it’s not just a theory that the Targaryens practised incest to preserve their dragon riding powers, it’s a stated fact in the books. Polygamy appears to just be for added fun rather than any genetic or magical necessity – a symptom of the depravity of Valyria.

From Aegon the Conqueror to Aegon the Unlikely

From Aegon the Conqueror onwards, the Targaryens married as so.


I promise: that looked a lot more in focus on my phone when I took it! 

Aegon married his sisters Visenya and Rhaenys. Aegon and Rhaenys have one child, Aenys; Aegon and Visenya have one child, Maegor.

Aenys married Alyssa Velaryon. Maegor (son of Visenya and Aegon) married lots, including Rhaena Targaryen, daughter of Aenys and Alyssa.

After Maegor’s death, Rhaena married her brother Aegon, and their other siblings Jaehaerys and Alysanne Targaryen also married.

Jaehaerys and Alysanne’s had many children! Unfortunately not all of them made it to adulthood. Of those who survived,

  • Daella Targaryen married Rodrick Arryn (and had Aemma Arryn who later married Viserys I and was the mother of Rhaenyra,)
  • Aemon (their youngest) married Jocelyn Baratheon (daughter of Alyssa Velaryon and Robar Baratheon,)
  • and Baelon and Alyssa (siblings) married and produced Viserys I, Aegon and Daemon.

Viserys marries Aemma Arryn, produces Rhaenyra; Aemma dies, he marries Alicent Hightower, they have Daeron, Aemond, Aegon and Helaena.

Rhaenyra first marries Laenor Velaryon, who is the grandson of Aemon son of Jaehaerys. Her kids named Velaryon are probably not Velaryons, but they all die unmarried anyway. She marries her uncle Daemon, and has more children: Viserys II, Aegon III and the daughter who was stillborn when the Dance of the Dragons kicked off.

It’s notable that at the time of the Dance of the Dragons, it was ‘known’ to the Valryian families of Westeros, House Targaryen and House Velaryon, that their bloodlines were the only who could control dragons – or at least, that’s what they believed. 

Nettles’ ability to tame Sheepstealer without any known Valyrian heritage, not even through ‘first night’ rape of her mother or grandmother, throws this ‘fact’ into disarray – dragons can be tamed through normal means of animal training. This is important for Tyrion’s future plot line, and throws a spanner in the works of the theory that dragonblood is necessary to be a dragonrider. However, perhaps this is simply the exception that proves the rule? Maybe dragons that have been tamed to a bloodline don’t necessarily require dragonblood, but new ones do? 

Of Viserys and Alicent Hightower’s children, Aegon and Helaena marry, and have Jaehaera, Jaehaerys and Maelor.

Jaehaera and Aegon III marry to link up the feuding lines of the Dance, but Jaehaera dies tragically young. Aegon the Unlucky then marries Daenaera Velaryon. They have 5 children: Rhaena, Baelor (the Blessed), Daena (the Defiant), Daeron (the Young Dragon) and Elaena. Elaena is quite interesting – she marries 3 times, and spreads the Targaryen blood through the Plumms and the Penroses. Daena is the mother of Daemon Waters, who became Daemon Blackfyre.

Viserys II married Larra Rogare of Lys, with whose family he was fostered in exile following the Dance of the Dragons. They had 3 children: Aegon IV (the Unworthy,) Aemon (the Dragonknight) and Naerys. Larra Rogare is described as “tall and willowy, with the silver-gold hair and purple eyes of Valyria,” giving the Targaryens a new injection of fresh Valyrian blood from outside the limited family bloodlines.

Aegon and Naerys were forced to marry by their father, even though Naerys had a better relationship with Aemon and was so pious she wanted to be a septa. What is interesting is that we are not told why – unlike with Aerys II and Rhaella later on, we are not told that Viserys II believed there was any prophecy that required his children to marry. It seems to have been arranged so that the eldest son and heir had a Targaryen wife, as dictated by the family’s historical reliance on incest to maintain a pure, dragonriding bloodline.

The reason that this is interesting is that by this stage, the dragons were dead. There was no reason to continue the incest. This suggests that Viserys II and the Targaryens who followed him had forgotten why their house and other Valryian dragonlords practised incest.

The mysteries of breeding and taming dragons were lost in time well before Aenar Targaryen heeded the warning of his daughter Daenys to flee to Dragonstone. The Targaryens in Westeros continued to practise incest not because they knew for certain that it helped them control dragons, but because it was the thing that Valyrians did. It was part of their ‘otherness’ that, they believed, made them better than the other nobles of Westeros.

Aegon IV and Naerys had 2 children: Daeron II and Daenerys, who was married to Maron Martell.

Daeron married Mariah Martell, and they had Baelor Breakspear, Aerys I, Rhaegel and Maekar. Baelor married Jena Dondarrion, Aerys married Aelinor Penrose, Rhaegal married Alys Arryn and Maekar married Dyanna Dayne. Baelor and Maekar married into ‘fresh’ gene pools, but we can infer that Aelinor and Alys had Targaryen ancestry from marriages made in generations past.

Baelor Breakspear and Jena Dondarrion had Valarr and Matarys (two sons.) Valarr married Kiera of Tyrosh but died in the Great Spring Sickness. Kiera went on to marry Daeron the Drunken (son of Maekar) and produce Vaella (the poor simple girl who died early.)

Aerys and Aelinor Penrose had no children as Aerys was more interested in scrolls than attending to his husbandly duties.

Rhaegel and Alys Arryn had three children, the twins Aelora and Aelor (who were married) and Daenora, who would go on to marry Aerion ‘Brightflame’ and produce Maegor, the baby boy who mysteriously disappears from Westerosi history and I think might be the father of Varys (and maybe Serra)

Maekar’s children we know and love.

  • Daeron the Drunken marries his cousin Valarr’s widow, has a girl who dies young.
  • Aerion marries his cousin Daenora, drinks wildfire and goes boom.
  • Aemon became a maester of the Citadel.
  • Daella is not listed as being married, nor is Rhae – most likely to preserve the mysteries of future Dunk and Egg books and the likely Targaryen/Dunk the Lunk ancestry of Brienne of Tarth.
  • Aegon V the Unlikely or the Fortunate married Betha Blackwood.

The more immediate Targaryen family history

Aegon and Betha had:

  • Duncan the Small (marries Jenny of Oldstones,)
  • Jaehaerys and Shaera (siblings who marry,)
  • Daeron who was betrothed to Olenna Redwyne but was probably gay so that didn’t work out,
  • and Rhaelle who married Ormund Baratheon and is the grandmother of Robert, Stannis and Renly.

Jaehaerys and Shaera had Aerys II and Rhaella, and Jenny’s woodswitch prophecised that the Prince That Was Promised would come from their line so they were forced to marry.

Unlike the forced marriage of Aegon IV and Naerys, Aerys and Rhaella were forced to marry in order to fulfil a prophecy. The ancient Valyrian dragonlord practice of incestuous marriage was useful to normalise this marriage, but it was not explicit that these two had to marry to carry on the dragonriding gene.

And then we get to the present – Rhaegar, Viserys and Daenerys.

While Rhaegar and Daenerys married outside of the Targaryen line, it’s pretty clear that had Aerys and Rhaella had a daughter old enough to marry Rhaegar, he would have been expected to marry her. Similarly, Viserys behaves that he’s been cheated out of his ‘proper’ marriage to Daenerys by their poverty and necessity to marry Khal Drogo to get the Dothraki army for his invasion.

Breaking down the numbers + what it means for the future ASOIAF story

Targaryens married to near family (siblings, first cousins, nieces/nephews/aunts/uncles): 17

Targaryens married outside the house (including marrying other houses with Targaryen ancestry but not in the immediate family): 25

While the Targaryen family tree folds back in on itself repeatedly, they aren’t quite at Hapsburg levels of constant incest. Of the named Targaryens, there are 25 marriages outside of the family (albeit often to other houses that have intermarried with Targaryens in the past, such as House Arryn, House Velaryon and House Martell.) There are only 17 marriages of close family incest – still 17 too many for some, but not the overwhelming preponderance that you think the Targaryens have when you first read the books.

(To be clear, I counted marriages, not people – as some people marry more than once.) 

More importantly, we can deduce a few things from the explicit references in the text:

Incestuous and polygamous marriages were common in the Valryian Freehold.

It’s not clear what polygamy has to do with dragonriding, and is more likely just an example of Valyrian decadence and depravity.

But the practice of incest is repeatedly explained in-universe as having something to do with dragonriding. “The blood of the dragon” is not just a Targaryen phrase: it is a Valyrian phrase. The blood of the dragon is kept pure through intermarriage. Why?

If only Valyrian blood is required to ride a dragon, why did Valyrians within the Freehold before the Doom practise incest? This suggests that the ability to ride particular dragons has something to do with particular bloodlines. Remember, dragons in Planetos live for multiple generations. Aegon the Conqueror’s dragon was ridden by Maegor, and Jaehaerys and Viserys I before Balerion the Black Dread finally passed on.

The Targaryens practised incest as much for preserving their ‘superiority’ as they did for preserving dragonriding powers.

While the Faith succeeded in getting the Targaryens to abolish their practice of polygamous marriage, they did not succeed in getting the royal house to move away from incest. Interestingly, it does not appear that the other Valyrian houses, Velaryon and Celtigar, who followed their dragonlord Aenar Targaryen to Westeros when Daenys the Dreamer foretold the Doom, practised incest. The Velaryons in particular intermarried frequently with the Targaryens and the Celtigars, but we do not have information in TWOIAF or beyond that indicate that incestuous marriage was practised by the Velaryons or Celitgars.

Thus, it was only House Targaryen who insisted on incest, even before the Conquest. They carried this practice of the great dragonlords of Valyria to Dragonstone and beyond. The Velaryons and Celtigars were “lesser houses” sworn to House Targaryen – implying that within Valyrian society, there was a rigid hierarchy between the dragonlords and those who served them. The dragonlords were special, and married their siblings, cousins and aunts or uncles; but their servers simply married each other.

We can also see from the diverse remnants of Valyrian heritage across Essos that this practice of incest was restricted to the ‘special’ dragonriding nobility only – otherwise the Valyrians of Essos would not be described as beautiful but deformed. Albeit this assumes that the laws of genetics that apply to this world and led to the infamous Hapsburg jaw apply to Planetos… and there are problems with making this assumption. Frequently the dominant traits of particularly houses in Westeros, not just amongst Valyrians but amongst the rest of Westeros’ nobility are traits that we understand to be recessive. For instance: the “Tully look” of red hair and blue eyes – both of these traits are recessive traits. However Ned Stark and Catelyn Tully manage to have 3/5 children with recessive traits, and Ned’s parents, grandparents and damn near the entire North are described as dark haired and grey eyed. So maybe recessive traits are a furphy that we should ignore in Westeros?

Do you necessarily need to be of the “blood of the dragon” to be a dragonrider?

Nettles is key.

She was a peasant girl from the Crownlands, who was assumed to be a dragonseed – i.e. someone who has Valyrian blood through rape perpetrated by Targaryen and Velaryon lords practising the right of first night. (This isn’t a GRRM invention either – it happened in our world for far too long as well.) During the Dance of the Dragons, the Blacks (supporting Rhaenyra Targaryen’s claim to the Iron Throne) found themselves with a surplus of dragons and a deficit of dragonriders after the deaths of Rhaenyra’s elder sons and cousin/mother-in-law Rhaenys (the ‘Queen Who Never Was’.)

Side note: Trying to work out what the relationship between Rhaenys and Rhaenyra is a great example of the Targaryen family tree folding back in on itself. The only way to do it is to put people on the family tree more than once – as shown here, where I’ve highlighted all the people who have to appear on the tree more than once for it to look even remotely legible.


  • Rhaenys is the daughter of Aemon Targaryen and Jocelyn Baratheon. Aemon Targaryen was the second son of Jaehaerys the Concilator and Good Queen Alysanne.
  • Aemon’s sister Daella married Rodrick Arryn, and they had Aemma Arryn
  • Aemma Arryn married Viserys I, who was the son of Aemon and Daella’s other siblings, Baelon and Alyssa. Aemma Arryn and Viserys I Targaryen had Rhaenyra Targaryen
  • Rhaenys Targaryen married Corlys Velaryon, and they had Laenor Targaryen, who was Rhaenyra’s first husband. Their daughter Laena married Daemon Targaryen, brother of Viserys I and second husband (after Laena’s death) of Rhaenyra
  • So Rhaenys is Rhaenyra’s cousin, and mother-in-law. I think. She’s possibly related in other ways too… 

Anyway. The Blacks put out a call for anyone who knew (or thought) that they had Targaryen blood in their veins, albeit from the wrong side of the bed sheets, to come and try to tame a dragon.

This leads to the circuitous logic of deciding that Nettles was a dragonseed.

She was assumed to be a dragonseed because she rode a dragon. However I believe that this accepted wisdom within TWOIAF is a deliberate red herring by GRRM: the point to Nettles, in a narrative sense, is that she demonstrates that you don’t necessarily need dragonblood to ride a dragon. The assumption that she has dragonblood because she is a dragonrider is arse about face: it should be that she was a dragonrider, therefore she may have dragonblood.

Why is this important? Because Daenerys has three dragons, and while Rhaegar and Quaithe might have told her “the dragon has three heads”, she is the only known person in the world that has proper, uncontested Valyrian dragonlord heritage. She is the only blood of the dragon. (Y’know… except for Jon Snow, and possibly Varys, and maybe Aegon VI even if he’s not the son of Rhaegar….)

But for all the potential hidden Targaryens out there, the one person who I think is definitely NOT Targaryen is Tyrion Lannister. However, I do think he will ride a dragon.

One thing we are told about Tyrion is that he spent his life reading:

A mind needs books as a sword needs a whetstone if it is to keep its edge

During his pre-enslavement exile, Tyrion makes himself spend time recalling things he has read, and writing them down, to break up his periods of drinking and depression.

What books in particular does he focus on?

As far as we know, Nettles was not literate. It’s unlikely that she ever read the works of Septon Barth, Galendro, Munkun or Thomax on how to train a dragon. But she was a shepherd. She knew how to tame animals. She fed Sheepstealer a sheep every day until the dragon let her climb aboard.

Nettles made no claims that she was a dragonseed, but everyone assumed that she was one because she rode a dragon. It’s that element of doubt that makes me think that the circumstantial evidence GRRM presents in the story of Nettles actually goes to the reverse of the thing everyone wants to prove.

Nettles, like Tyrion, rode (or will ride) a dragon because she figured out how to tame a dragon. Her dragonriding introduces doubt to the concept that only the chosen few Valryian dragonlord families can ride dragons. It also introduces the concept that anyone can train a dragon if they try hard enough – and Tyrion would certainly be motivated to try.

How did the Valyrians become dragonriders in the first place?

How did the nobles become noble in the first place? They took it! At the point of a sword. I’ll do the same with a lance!”

“A blunted lance!”

“Oh no matter Wat! A man can change his stars!”

Like Heath Ledger’s William Thatcher, who aspired to be a famous, tournament-winning knight (in a medieval setting that apparently didn’t have hedge knights) I too wonder how the nobles became noble.

Except, I wonder how the Valyrians became dragonriders.

One clue to the how of dragon-taming lies in the peculiar item that Euron Greyjoy brings to the Kingsmoot as proof of his claim to the Seastone Chair.

The horn he blew was shiny black and twisted, and taller than a man as he held it with both hands. It was bound about with bands of red gold and dark steel, incised with ancient Valyrian glyphs that seemed to glow redly as the sound swelled….

The cheeks of the tattooed man were so puffed out they looked about to burst, and the muscles in his chest twitched in a way that it made it seem as if the bird were about to rip free of his flesh and take wing. And now the glyphs were burning brightly, every line and letter shimmering with white fire. On and on and on the sound went, echoing amongst the howling hills behind them and across the waters of Nagga’s Cradle to ring against the mountains of Great Wyk, on and on and on until it filled the whole wet world….  A thin wisp of smoke was rising from the horn, and the priest saw blood and blisters upon the lips of the man who’d sounded it. The bird on his chest was bleeding too.

… “That horn you heard I found amongst the smoking ruins that were Valyria, where no man has dared to walk but me. You heard its call, and felt its power. It is a dragon horn, bound with bands of red gold and Valyrian steel graven with enchantments. The dragonlords of old sounded such horns, before the Doom devoured them. With this horn, ironmen, I can bind dragons to my will.

6 thoughts on “House Targaryen, dragonriding and genetics

  1. Skull of the Greatjon says:

    The “blood of the dragon” is found in characters with no Valyrian lineage like Lord Beric, Lady Stoneheart and (probably) Melisandre. It was also found in certain of the Valyrians who practiced resurrection through bloodmagic, which is how they hatched and rode dragons. Daenerys, whose resurrection with bloodmagic is depicted in the “Fever Dream” chapter of AGOT, also has it, and that’s how she hatched dragons.

    This is a very neat and textually supported explanation for many of the events in the series.


    1. LadyKnitsALot says:

      Could you give references to these characters talking about the blood of the dragon? I’m not quite sure what point you’re making but I’m interested.


  2. think you are wrong about Nettles.
    First of all, just because she doesn’t know where it comes from, it doesn’t mean she doesn’t have Valyrian blood. She may not been a daughter of a Targaryen, but she could have been a granddaughter of an obscure Targaryen bastard who won the genetic lottery and inherited the ‘right’ drop of dragonblood. The description we get from her is that she was “brown”. In the main novels we meet plenty of brown-skinned Targaryen descendants: the Martells and the Sand Snakes, Brown Ben Plumm, and Bellegere Otherys, the Black Pearl of Braavos (“brown pearl” as Arya call her).

    As for her way of getting the dragon to trust her… well, what did you expect? She didn’t have a dragonhorn that the Valyrians traditionally used to get the dragon under control. She needed to go slower and be more careful… how to get an animal’s trust? By feeding it.

    But if it was truly as easy to get a dragon’s trust by feeding it… then how it comes that the personnel feeding the dragons have never bonded with any of the dragons, the untaken ones, the hatchlings etc.? Seems strange, no?

    We also know that at the start of the war Rhaenyra allowed people with no known Valyrian heritage to attempt to mount her dragons… with no success.

    The last thing, GRRM often uses references to works of other fantasy authors. One of his favorite fellow writers is Robin Hobb. In Hobin’s books there is a character of a girl named Nettle that is a secret bastard of a royal bastard. Maybe not a coincidence?


    1. LadyKnitsALot says:

      My beef with the in-text/in-universe assumption that Nettles is a dragonseed because she was a dragonrider is that it presumes riding = Valyrian heritage.

      The proper construct is “Nettles MAY be a dragonseed because she was a dragonrider – or she may have simply tamed a dragon.”


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